Speaker: Prof. Paul Olsen, Earth and Environmental Sciences at Columbia University

Time: 10:00-11:30 a.m., Jun 25, 2024, GMT+8

Venue: Rm 209, Science teaching building, PKU

Abstract: 

The end-Triassic mass extinction at 202 million years ago (Ma) wiped out most of animal diversity on land allowing modern forms to take over, with dinosaurs becoming especially dominant until another mass extinction at 66 Ma wiped them all out, except birds. Why? Why did dinosaurs, minor parts of the land community of the Triassic, take over? | will show that the reason was that the seasonally freezing, polar regions of the Earth were incubators of land life where animals evolved adaptations, especially insulation, for surviving extreme cold as a normal part of existence. When giant eruptions covering parts of four continents produced intense volcanic winters from sulfur aerosols perhaps freezing even the tropics, the cold killed off all medium- to large-sized land reptiles except the insulated dinosaurs. I will show how evidence of freezing winters from the Junggar Basin, Xinjiang, which was above the Arctic Circle at the time, holds the key to this mystery.

Source: Peking University School of Pharmaceutical Sciences